From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg KH <greg@kroah.com>,
linux-pci@atrey.karlin.mff.cuni.cz,
Linux-pm mailing list <linux-pm@lists.osdl.org>,
Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: [linux-pm] Bug in PCI core
Date: Fri, 13 Oct 2006 11:01:03 +1000 [thread overview]
Message-ID: <1160701263.4792.179.camel@localhost.localdomain> (raw)
In-Reply-To: <Pine.LNX.4.44L0.0610111632240.6353-100000@iolanthe.rowland.org>
On Wed, 2006-10-11 at 16:41 -0400, Alan Stern wrote:
> When a PCI device is suspended, its driver calls pci_save_state() so that
> the config space can be restored when the device is resumed. Then the
> driver calls pci_set_power_state().
>
> However pci_set_power_state() calls pci_block_user_cfg_access(), and that
> routine calls pci_save_state() again. This overwrites the saved state
> with data in which memory, I/O, and bus master accesses are disabled. As
> a result, when the device is resumed it doesn't work.
>
> Obviously pci_block_user_cfg_access() needs to be fixed. I don't know the
> right way to fix it; hopefully somebody else does.
Well, blocking user cfg access snapshots the config space to be able to
respond to user space while the device is offline. Maybe it should be
done from a separate config space image buffer ? ugh....
Ben.
next prev parent reply other threads:[~2006-10-13 1:01 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-11 20:41 Bug in PCI core Alan Stern
2006-10-13 1:01 ` Benjamin Herrenschmidt [this message]
2006-10-13 8:50 ` Adam Belay
2006-10-13 9:16 ` Benjamin Herrenschmidt
2006-10-13 9:31 ` Martin Mares
2006-10-13 12:25 ` [linux-pm] " Benjamin Herrenschmidt
2006-10-13 14:29 ` Alan Stern
2006-10-13 15:26 ` [linux-pm] " Alan Cox
2006-10-13 15:29 ` Arjan van de Ven
2006-10-13 16:06 ` Alan Cox
2006-10-13 16:34 ` Adam Belay
2006-10-13 16:36 ` [linux-pm] " Matthew Wilcox
2006-10-13 17:09 ` Alan Cox
2006-10-13 16:49 ` Matthew Wilcox
2006-10-13 17:34 ` Alan Cox
2006-10-13 17:13 ` Arjan van de Ven
2006-10-13 17:57 ` Alan Stern
2006-10-13 19:18 ` [linux-pm] " Matthew Wilcox
2006-10-13 20:59 ` Alan Stern
2006-10-13 19:30 ` Adam Belay
2006-10-13 23:00 ` Benjamin Herrenschmidt
2006-10-14 2:33 ` Alan Stern
2006-10-14 3:04 ` [linux-pm] " Roland Dreier
2006-10-14 3:07 ` Matthew Wilcox
2006-10-14 3:19 ` Bill Randle
2006-10-14 5:47 ` Greg KH
2006-10-13 17:01 ` Adam Belay
2006-10-13 16:40 ` Adam Belay
2006-10-13 20:48 ` [linux-pm] " Pavel Machek
2006-10-14 5:34 ` Greg KH
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